// This code is derived from jcifs smb client library <jcifs at samba dot org>
// Ported by J. Arturo <webmaster at komodosoft dot net>
//  
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
using System;

namespace SharpCifs.Util
{
    /// <summary>
    /// This code is derived from the above source
    /// JCIFS API
    /// Norbert Hranitzky
    /// <p>and modified again by Michael B.
    /// </summary>
    /// <remarks>
    /// This code is derived from the above source
    /// JCIFS API
    /// Norbert Hranitzky
    /// <p>and modified again by Michael B. Allen
    /// </remarks>
    public class DES
    {
        private int[] _encryptKeys = new int[32];

        private int[] _decryptKeys = new int[32];

        private int[] _tempInts = new int[2];

        public DES()
        {
        }

        public DES(byte[] key)
        {
            // DesCipher - the DES encryption method
            //
            // The meat of this code is by Dave Zimmerman <dzimm@widget.com>, and is:
            //
            // Copyright (c) 1996 Widget Workshop, Inc. All Rights Reserved.
            //
            // Permission to use, copy, modify, and distribute this software
            // and its documentation for NON-COMMERCIAL or COMMERCIAL purposes and
            // without fee is hereby granted, provided that this copyright notice is kept
            // intact.
            //
            // WIDGET WORKSHOP MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY
            // OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
            // TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
            // PARTICULAR PURPOSE, OR NON-INFRINGEMENT. WIDGET WORKSHOP SHALL NOT BE LIABLE
            // FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
            // DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
            //
            // THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
            // CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
            // PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
            // NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
            // SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
            // SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
            // PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  WIDGET WORKSHOP
            // SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
            // HIGH RISK ACTIVITIES.
            //
            //
            // The rest is:
            //
            // Copyright (C) 1996 by Jef Poskanzer <jef@acme.com>.  All rights reserved.
            //
            // Copyright (C) 1996 by Wolfgang Platzer
            // email: wplatzer@iaik.tu-graz.ac.at
            //
            // All rights reserved.
            //
            // Redistribution and use in source and binary forms, with or without
            // modification, are permitted provided that the following conditions
            // are met:
            // 1. Redistributions of source code must retain the above copyright
            //    notice, this list of conditions and the following disclaimer.
            // 2. Redistributions in binary form must reproduce the above copyright
            //    notice, this list of conditions and the following disclaimer in the
            //    documentation and/or other materials provided with the distribution.
            //
            // THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
            // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
            // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
            // ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
            // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
            // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
            // OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
            // HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
            // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
            // OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
            // SUCH DAMAGE.
            //
            // Constructor, byte-array key.
            if (key.Length == 7)
            {
                byte[] key8 = new byte[8];
                MakeSmbKey(key, key8);
                SetKey(key8);
            }
            else
            {
                SetKey(key);
            }
        }

        public static void MakeSmbKey(byte[] key7, byte[] key8)
        {
            int i;
            key8[0] = unchecked((byte)((key7[0] >> 1) & unchecked(0xff)));
            key8[1] = unchecked((byte)((((key7[0] & unchecked(0x01)) << 6)
                    | (((key7[1] & unchecked(0xff)) >> 2) & unchecked(0xff))) & unchecked(0xff)));
            key8[2] = unchecked((byte)((((key7[1] & unchecked(0x03)) << 5)
                    | (((key7[2] & unchecked(0xff)) >> 3) & unchecked(0xff))) & unchecked(0xff)));
            key8[3] = unchecked((byte)((((key7[2] & unchecked(0x07)) << 4)
                    | (((key7[3] & unchecked(0xff)) >> 4) & unchecked(0xff))) & unchecked(0xff)));
            key8[4] = unchecked((byte)((((key7[3] & unchecked(0x0F)) << 3)
                    | (((key7[4] & unchecked(0xff)) >> 5) & unchecked(0xff))) & unchecked(0xff)));
            key8[5] = unchecked((byte)((((key7[4] & unchecked(0x1F)) << 2)
                    | (((key7[5] & unchecked(0xff)) >> 6) & unchecked(0xff))) & unchecked(0xff)));
            key8[6] = unchecked((byte)((((key7[5] & unchecked(0x3F)) << 1)
                    | (((key7[6] & unchecked(0xff)) >> 7) & unchecked(0xff))) & unchecked(0xff)));
            key8[7] = unchecked((byte)(key7[6] & unchecked(0x7F)));
            for (i = 0; i < 8; i++)
            {
                key8[i] = unchecked((byte)(key8[i] << 1));
            }
        }

        /// Set the key.
        public virtual void SetKey(byte[] key)
        {
            // CHECK PAROTY TBD
            Deskey(key, true, _encryptKeys);
            Deskey(key, false, _decryptKeys);
        }

        // Turn an 8-byte key into internal keys.
        private void Deskey(byte[] keyBlock, bool encrypting, int[] knL)
        {
            int i;
            int j;
            int l;
            int m;
            int n;
            int[] pc1M = new int[56];
            int[] pcr = new int[56];
            int[] kn = new int[32];
            for (j = 0; j < 56; ++j)
            {
                l = _pc1[j];
                m = l & 0x7;
                pc1M[j] = ((keyBlock[(int)(((uint)l) >> 3)] & _bytebit[m]) != 0) ? 1 : 0;
            }
            for (i = 0; i < 16; ++i)
            {
                if (encrypting)
                {
                    m = i << 1;
                }
                else
                {
                    m = (15 - i) << 1;
                }
                n = m + 1;
                kn[m] = kn[n] = 0;
                for (j = 0; j < 28; ++j)
                {
                    l = j + _totrot[i];
                    if (l < 28)
                    {
                        pcr[j] = pc1M[l];
                    }
                    else
                    {
                        pcr[j] = pc1M[l - 28];
                    }
                }
                for (j = 28; j < 56; ++j)
                {
                    l = j + _totrot[i];
                    if (l < 56)
                    {
                        pcr[j] = pc1M[l];
                    }
                    else
                    {
                        pcr[j] = pc1M[l - 28];
                    }
                }
                for (j = 0; j < 24; ++j)
                {
                    if (pcr[_pc2[j]] != 0)
                    {
                        kn[m] |= _bigbyte[j];
                    }
                    if (pcr[_pc2[j + 24]] != 0)
                    {
                        kn[n] |= _bigbyte[j];
                    }
                }
            }
            Cookey(kn, knL);
        }

        private void Cookey(int[] raw, int[] knL)
        {
            int raw0;
            int raw1;
            int rawi;
            int knLi;
            int i;
            for (i = 0, rawi = 0, knLi = 0; i < 16; ++i)
            {
                raw0 = raw[rawi++];
                raw1 = raw[rawi++];
                knL[knLi] = (raw0 & unchecked(0x00fc0000)) << 6;
                knL[knLi] |= (raw0 & unchecked(0x00000fc0)) << 10;
                knL[knLi] |= (int)(((uint)(raw1 & unchecked(0x00fc0000))) >> 10);
                knL[knLi] |= (int)(((uint)(raw1 & unchecked(0x00000fc0))) >> 6);
                ++knLi;
                knL[knLi] = (raw0 & unchecked(0x0003f000)) << 12;
                knL[knLi] |= (raw0 & unchecked(0x0000003f)) << 16;
                knL[knLi] |= (int)(((uint)(raw1 & unchecked(0x0003f000))) >> 4);
                knL[knLi] |= (raw1 & unchecked(0x0000003f));
                ++knLi;
            }
        }

        /// Encrypt a block of eight bytes.
        private void Encrypt(byte[] clearText, int clearOff, byte[] cipherText, int cipherOff)
        {
            SquashBytesToInts(clearText, clearOff, _tempInts, 0, 2);
            Des(_tempInts, _tempInts, _encryptKeys);
            SpreadIntsToBytes(_tempInts, 0, cipherText, cipherOff, 2);
        }

        /// Decrypt a block of eight bytes.
        private void Decrypt(byte[] cipherText, int cipherOff, byte[] clearText, int clearOff)
        {
            SquashBytesToInts(cipherText, cipherOff, _tempInts, 0, 2);
            Des(_tempInts, _tempInts, _decryptKeys);
            SpreadIntsToBytes(_tempInts, 0, clearText, clearOff, 2);
        }

        // The DES function.
        private void Des(int[] inInts, int[] outInts, int[] keys)
        {
            int fval;
            int work;
            int right;
            int leftt;
            int round;
            int keysi = 0;
            leftt = inInts[0];
            right = inInts[1];
            work = (((int)(((uint)leftt) >> 4)) ^ right) & unchecked(0x0f0f0f0f);
            right ^= work;
            leftt ^= (work << 4);
            work = (((int)(((uint)leftt) >> 16)) ^ right) & unchecked(0x0000ffff);
            right ^= work;
            leftt ^= (work << 16);
            work = (((int)(((uint)right) >> 2)) ^ leftt) & unchecked(0x33333333);
            leftt ^= work;
            right ^= (work << 2);
            work = (((int)(((uint)right) >> 8)) ^ leftt) & unchecked(0x00ff00ff);
            leftt ^= work;
            right ^= (work << 8);
            right = (right << 1) | (((int)(((uint)right) >> 31)) & 1);
            work = (leftt ^ right) & unchecked((int)(0xaaaaaaaa));
            leftt ^= work;
            right ^= work;
            leftt = (leftt << 1) | (((int)(((uint)leftt) >> 31)) & 1);
            for (round = 0; round < 8; ++round)
            {
                work = (right << 28) | ((int)(((uint)right) >> 4));
                work ^= keys[keysi++];
                fval = _sp7[work & unchecked(0x0000003f)];
                fval |= _sp5[((int)(((uint)work) >> 8)) & unchecked(0x0000003f)];
                fval |= _sp3[((int)(((uint)work) >> 16)) & unchecked(0x0000003f)];
                fval |= _sp1[((int)(((uint)work) >> 24)) & unchecked(0x0000003f)];
                work = right ^ keys[keysi++];
                fval |= _sp8[work & unchecked(0x0000003f)];
                fval |= _sp6[((int)(((uint)work) >> 8)) & unchecked(0x0000003f)];
                fval |= _sp4[((int)(((uint)work) >> 16)) & unchecked(0x0000003f)];
                fval |= _sp2[((int)(((uint)work) >> 24)) & unchecked(0x0000003f)];
                leftt ^= fval;
                work = (leftt << 28) | ((int)(((uint)leftt) >> 4));
                work ^= keys[keysi++];
                fval = _sp7[work & unchecked(0x0000003f)];
                fval |= _sp5[((int)(((uint)work) >> 8)) & unchecked(0x0000003f)];
                fval |= _sp3[((int)(((uint)work) >> 16)) & unchecked(0x0000003f)];
                fval |= _sp1[((int)(((uint)work) >> 24)) & unchecked(0x0000003f)];
                work = leftt ^ keys[keysi++];
                fval |= _sp8[work & unchecked(0x0000003f)];
                fval |= _sp6[((int)(((uint)work) >> 8)) & unchecked(0x0000003f)];
                fval |= _sp4[((int)(((uint)work) >> 16)) & unchecked(0x0000003f)];
                fval |= _sp2[((int)(((uint)work) >> 24)) & unchecked(0x0000003f)];
                right ^= fval;
            }
            right = (right << 31) | ((int)(((uint)right) >> 1));
            work = (leftt ^ right) & unchecked((int)(0xaaaaaaaa));
            leftt ^= work;
            right ^= work;
            leftt = (leftt << 31) | ((int)(((uint)leftt) >> 1));
            work = (((int)(((uint)leftt) >> 8)) ^ right) & unchecked(0x00ff00ff);
            right ^= work;
            leftt ^= (work << 8);
            work = (((int)(((uint)leftt) >> 2)) ^ right) & unchecked(0x33333333);
            right ^= work;
            leftt ^= (work << 2);
            work = (((int)(((uint)right) >> 16)) ^ leftt) & unchecked(0x0000ffff);
            leftt ^= work;
            right ^= (work << 16);
            work = (((int)(((uint)right) >> 4)) ^ leftt) & unchecked(0x0f0f0f0f);
            leftt ^= work;
            right ^= (work << 4);
            outInts[0] = right;
            outInts[1] = leftt;
        }

        /// Encrypt a block of bytes.
        public virtual void Encrypt(byte[] clearText, byte[] cipherText)
        {
            Encrypt(clearText, 0, cipherText, 0);
        }

        /// Decrypt a block of bytes.
        public virtual void Decrypt(byte[] cipherText, byte[] clearText)
        {
            Decrypt(cipherText, 0, clearText, 0);
        }

        /// <summary>encrypts an array where the length must be a multiple of 8</summary>
        public virtual byte[] Encrypt(byte[] clearText)
        {
            int length = clearText.Length;
            if (length % 8 != 0)
            {
                Console.Out.WriteLine("Array must be a multiple of 8");
                return null;
            }
            byte[] cipherText = new byte[length];
            int count = length / 8;
            for (int i = 0; i < count; i++)
            {
                Encrypt(clearText, i * 8, cipherText, i * 8);
            }
            return cipherText;
        }

        /// <summary>decrypts an array where the length must be a multiple of 8</summary>
        public virtual byte[] Decrypt(byte[] cipherText)
        {
            int length = cipherText.Length;
            if (length % 8 != 0)
            {
                Console.Out.WriteLine("Array must be a multiple of 8");
                return null;
            }
            byte[] clearText = new byte[length];
            int count = length / 8;
            for (int i = 0; i < count; i++)
            {
                Encrypt(cipherText, i * 8, clearText, i * 8);
            }
            return clearText;
        }

        private static byte[] _bytebit =
        {
            unchecked(unchecked(0x80)),
            unchecked(unchecked(0x40)),
            unchecked(unchecked(0x20)),
            unchecked(unchecked(0x10)),
            unchecked(unchecked(0x08)),
            unchecked(unchecked(0x04)),
            unchecked(unchecked(0x02)),
            unchecked(unchecked(0x01))
        };

        private static int[] _bigbyte =
        {
            unchecked(0x800000), unchecked(0x400000), unchecked(0x200000),
            unchecked(0x100000), unchecked(0x080000), unchecked(0x040000),
            unchecked(0x020000), unchecked(0x010000), unchecked(0x008000),
            unchecked(0x004000), unchecked(0x002000), unchecked(0x001000),
            unchecked(0x000800), unchecked(0x000400), unchecked(0x000200),
            unchecked(0x000100), unchecked(0x000080), unchecked(0x000040),
            unchecked(0x000020), unchecked(0x000010), unchecked(0x000008),
            unchecked(0x000004), unchecked(0x000002), unchecked(0x000001)
        };

        private static byte[] _pc1 =
        {
            unchecked(56), unchecked(48), unchecked(40), unchecked(32),
            unchecked(24), unchecked(16), unchecked(8), unchecked(0),
            unchecked(57), unchecked(49), unchecked(41), unchecked(33),
            unchecked(25), unchecked(17), unchecked(9), unchecked(1),
            unchecked(58), unchecked(50), unchecked(42), unchecked(34),
            unchecked(26), unchecked(18), unchecked(10), unchecked(2),
            unchecked(59), unchecked(51), unchecked(43), unchecked(35),
            unchecked(62), unchecked(54), unchecked(46), unchecked(38),
            unchecked(30), unchecked(22), unchecked(14), unchecked(6),
            unchecked(61), unchecked(53), unchecked(45), unchecked(37),
            unchecked(29), unchecked(21), unchecked(13), unchecked(5),
            unchecked(60), unchecked(52), unchecked(44), unchecked(36),
            unchecked(28), unchecked(20), unchecked(12), unchecked(4),
            unchecked(27), unchecked(19), unchecked(11), unchecked(3)
        };

        private static int[] _totrot
            = { 1, 2, 4, 6, 8, 10, 12, 14, 15, 17, 19, 21, 23, 25, 27, 28 };

        private static byte[] _pc2 =
        {
            unchecked(13), unchecked(16), unchecked(10), unchecked(23),
            unchecked(0), unchecked(4), unchecked(2), unchecked(27),
            unchecked(14), unchecked(5), unchecked(20), unchecked(9),
            unchecked(22), unchecked(18), unchecked(11), unchecked(3),
            unchecked(25), unchecked(7), unchecked(15), unchecked(6),
            unchecked(26), unchecked(19), unchecked(12), unchecked(1),
            unchecked(40), unchecked(51), unchecked(30), unchecked(36),
            unchecked(46), unchecked(54), unchecked(29), unchecked(39),
            unchecked(50), unchecked(44), unchecked(32), unchecked(47),
            unchecked(43), unchecked(48), unchecked(38), unchecked(55),
            unchecked(33), unchecked(52), unchecked(45), unchecked(41),
            unchecked(49), unchecked(35), unchecked(28), unchecked(31)
        };

        private static int[] _sp1 =
        {
            unchecked(0x01010400), unchecked(0x00000000), unchecked(0x00010000),
            unchecked(0x01010404), unchecked(0x01010004), unchecked(0x00010404),
            unchecked(0x00000004), unchecked(0x00010000), unchecked(0x00000400),
            unchecked(0x01010400), unchecked(0x01010404), unchecked(0x00000400),
            unchecked(0x01000404), unchecked(0x01010004), unchecked(0x01000000),
            unchecked(0x00000004), unchecked(0x00000404), unchecked(0x01000400),
            unchecked(0x01000400), unchecked(0x00010400), unchecked(0x00010400),
            unchecked(0x01010000), unchecked(0x01010000), unchecked(0x01000404),
            unchecked(0x00010004), unchecked(0x01000004), unchecked(0x01000004),
            unchecked(0x00010004), unchecked(0x00000000), unchecked(0x00000404),
            unchecked(0x00010404), unchecked(0x01000000), unchecked(0x00010000),
            unchecked(0x01010404), unchecked(0x00000004), unchecked(0x01010000),
            unchecked(0x01010400), unchecked(0x01000000), unchecked(0x01000000),
            unchecked(0x00000400), unchecked(0x01010004), unchecked(0x00010000),
            unchecked(0x00010400), unchecked(0x01000004), unchecked(0x00000400),
            unchecked(0x00000004), unchecked(0x01000404), unchecked(0x00010404),
            unchecked(0x01010404), unchecked(0x00010004), unchecked(0x01010000),
            unchecked(0x01000404), unchecked(0x01000004), unchecked(0x00000404),
            unchecked(0x00010404), unchecked(0x01010400), unchecked(0x00000404),
            unchecked(0x01000400), unchecked(0x01000400), unchecked(0x00000000),
            unchecked(0x00010004), unchecked(0x00010400),
            unchecked(0x00000000), unchecked(0x01010004)
        };

        private static int[] _sp2 =
        {
            unchecked((int)(0x80108020)), unchecked((int)(0x80008000)), unchecked(0x00008000),
            unchecked(0x00108020), unchecked(0x00100000), unchecked(0x00000020),
            unchecked((int)(0x80100020)), unchecked((int)(0x80008020)), unchecked((int)(0x80000020)),
            unchecked((int)(0x80108020)), unchecked((int)(0x80108000)), unchecked((int)(0x80000000)),
            unchecked((int)(0x80008000)), unchecked(0x00100000), unchecked(0x00000020),
            unchecked((int)(0x80100020)), unchecked(0x00108000), unchecked(0x00100020),
            unchecked((int)(0x80008020)), unchecked(0x00000000), unchecked((int)(0x80000000)),
            unchecked(0x00008000), unchecked(0x00108020), unchecked((int)(0x80100000)),
            unchecked(0x00100020), unchecked((int)(0x80000020)), unchecked(0x00000000),
            unchecked(0x00108000), unchecked(0x00008020), unchecked((int)(0x80108000)),
            unchecked((int)(0x80100000)), unchecked(0x00008020), unchecked(0x00000000),
            unchecked(0x00108020), unchecked((int)(0x80100020)), unchecked(0x00100000),
            unchecked((int)(0x80008020)), unchecked((int)(0x80100000)), unchecked((int)(0x80108000)),
            unchecked(0x00008000), unchecked((int)(0x80100000)), unchecked((int)(0x80008000)),
            unchecked(0x00000020), unchecked((int)(0x80108020)), unchecked(0x00108020),
            unchecked(0x00000020), unchecked(0x00008000), unchecked((int)(0x80000000)),
            unchecked(0x00008020), unchecked((int)(0x80108000)), unchecked(0x00100000),
            unchecked((int)(0x80000020)), unchecked(0x00100020), unchecked((int)(0x80008020)),
            unchecked((int)(0x80000020)), unchecked(0x00100020), unchecked(0x00108000),
            unchecked(0x00000000), unchecked((int)(0x80008000)), unchecked(0x00008020),
            unchecked((int)(0x80000000)), unchecked((int)(0x80100020)), unchecked((int)(0x80108020)),
            unchecked(0x00108000)
        };

        private static int[] _sp3 =
        {
            unchecked(0x00000208), unchecked(0x08020200), unchecked(0x00000000),
            unchecked(0x08020008), unchecked(0x08000200), unchecked(0x00000000),
            unchecked(0x00020208), unchecked(0x08000200), unchecked(0x00020008),
            unchecked(0x08000008), unchecked(0x08000008), unchecked(0x00020000),
            unchecked(0x08020208), unchecked(0x00020008), unchecked(0x08020000),
            unchecked(0x00000208), unchecked(0x08000000), unchecked(0x00000008),
            unchecked(0x08020200), unchecked(0x00000200), unchecked(0x00020200),
            unchecked(0x08020000), unchecked(0x08020008), unchecked(0x00020208),
            unchecked(0x08000208), unchecked(0x00020200), unchecked(0x00020000),
            unchecked(0x08000208), unchecked(0x00000008), unchecked(0x08020208),
            unchecked(0x00000200), unchecked(0x08000000), unchecked(0x08020200),
            unchecked(0x08000000), unchecked(0x00020008), unchecked(0x00000208),
            unchecked(0x00020000), unchecked(0x08020200), unchecked(0x08000200),
            unchecked(0x00000000), unchecked(0x00000200), unchecked(0x00020008),
            unchecked(0x08020208), unchecked(0x08000200), unchecked(0x08000008),
            unchecked(0x00000200), unchecked(0x00000000), unchecked(0x08020008),
            unchecked(0x08000208), unchecked(0x00020000), unchecked(0x08000000),
            unchecked(0x08020208), unchecked(0x00000008), unchecked(0x00020208),
            unchecked(0x00020200), unchecked(0x08000008), unchecked(0x08020000),
            unchecked(0x08000208), unchecked(0x00000208), unchecked(0x08020000),
            unchecked(0x00020208), unchecked(0x00000008),unchecked(0x08020008),
            unchecked(0x00020200)
        };

        private static int[] _sp4 =
        {
            unchecked(0x00802001), unchecked(0x00002081), unchecked(0x00002081),
            unchecked(0x00000080), unchecked(0x00802080), unchecked(0x00800081),
            unchecked(0x00800001), unchecked(0x00002001), unchecked(0x00000000),
            unchecked(0x00802000), unchecked(0x00802000), unchecked(0x00802081),
            unchecked(0x00000081), unchecked(0x00000000), unchecked(0x00800080),
            unchecked(0x00800001), unchecked(0x00000001), unchecked(0x00002000),
            unchecked(0x00800000), unchecked(0x00802001), unchecked(0x00000080),
            unchecked(0x00800000), unchecked(0x00002001), unchecked(0x00002080),
            unchecked(0x00800081), unchecked(0x00000001), unchecked(0x00002080),
            unchecked(0x00800080), unchecked(0x00002000), unchecked(0x00802080),
            unchecked(0x00802081), unchecked(0x00000081), unchecked(0x00800080),
            unchecked(0x00800001), unchecked(0x00802000), unchecked(0x00802081),
            unchecked(0x00000081), unchecked(0x00000000), unchecked(0x00000000),
            unchecked(0x00802000), unchecked(0x00002080), unchecked(0x00800080),
            unchecked(0x00800081), unchecked(0x00000001), unchecked(0x00802001),
            unchecked(0x00002081), unchecked(0x00002081), unchecked(0x00000080),
            unchecked(0x00802081), unchecked(0x00000081), unchecked(0x00000001),
            unchecked(0x00002000), unchecked(0x00800001), unchecked(0x00002001),
            unchecked(0x00802080), unchecked(0x00800081), unchecked(0x00002001),
            unchecked(0x00002080), unchecked(0x00800000), unchecked(0x00802001),
            unchecked(0x00000080), unchecked(0x00800000), unchecked(0x00002000),
            unchecked(0x00802080)
        };

        private static int[] _sp5 =
        {
            unchecked(0x00000100), unchecked(0x02080100), unchecked(0x02080000),
            unchecked(0x42000100), unchecked(0x00080000), unchecked(0x00000100),
            unchecked(0x40000000), unchecked(0x02080000), unchecked(0x40080100),
            unchecked(0x00080000), unchecked(0x02000100), unchecked(0x40080100),
            unchecked(0x42000100), unchecked(0x42080000), unchecked(0x00080100),
            unchecked(0x40000000), unchecked(0x02000000), unchecked(0x40080000),
            unchecked(0x40080000), unchecked(0x00000000), unchecked(0x40000100),
            unchecked(0x42080100), unchecked(0x42080100), unchecked(0x02000100),
            unchecked(0x42080000), unchecked(0x40000100), unchecked(0x00000000),
            unchecked(0x42000000), unchecked(0x02080100), unchecked(0x02000000),
            unchecked(0x42000000), unchecked(0x00080100), unchecked(0x00080000),
            unchecked(0x42000100), unchecked(0x00000100), unchecked(0x02000000),
            unchecked(0x40000000), unchecked(0x02080000), unchecked(0x42000100),
            unchecked(0x40080100), unchecked(0x02000100), unchecked(0x40000000),
            unchecked(0x42080000), unchecked(0x02080100), unchecked(0x40080100),
            unchecked(0x00000100), unchecked(0x02000000), unchecked(0x42080000),
            unchecked(0x42080100), unchecked(0x00080100), unchecked(0x42000000),
            unchecked(0x42080100), unchecked(0x02080000), unchecked(0x00000000),
            unchecked(0x40080000), unchecked(0x42000000), unchecked(0x00080100),
            unchecked(0x02000100), unchecked(0x40000100), unchecked(0x00080000),
            unchecked(0x00000000), unchecked(0x40080000), unchecked(0x02080100),
            unchecked(0x40000100)
        };

        private static int[] _sp6 =
        {
            unchecked(0x20000010), unchecked(0x20400000), unchecked(0x00004000),
            unchecked(0x20404010), unchecked(0x20400000), unchecked(0x00000010),
            unchecked(0x20404010), unchecked(0x00400000), unchecked(0x20004000),
            unchecked(0x00404010), unchecked(0x00400000), unchecked(0x20000010),
            unchecked(0x00400010), unchecked(0x20004000), unchecked(0x20000000),
            unchecked(0x00004010), unchecked(0x00000000), unchecked(0x00400010),
            unchecked(0x20004010), unchecked(0x00004000), unchecked(0x00404000),
            unchecked(0x20004010), unchecked(0x00000010), unchecked(0x20400010),
            unchecked(0x20400010), unchecked(0x00000000), unchecked(0x00404010),
            unchecked(0x20404000), unchecked(0x00004010), unchecked(0x00404000),
            unchecked(0x20404000), unchecked(0x20000000), unchecked(0x20004000),
            unchecked(0x00000010), unchecked(0x20400010), unchecked(0x00404000),
            unchecked(0x20404010), unchecked(0x00400000), unchecked(0x00004010),
            unchecked(0x20000010), unchecked(0x00400000), unchecked(0x20004000),
            unchecked(0x20000000), unchecked(0x00004010), unchecked(0x20000010),
            unchecked(0x20404010), unchecked(0x00404000), unchecked(0x20400000),
            unchecked(0x00404010), unchecked(0x20404000), unchecked(0x00000000),
            unchecked(0x20400010), unchecked(0x00000010), unchecked(0x00004000),
            unchecked(0x20400000), unchecked(0x00404010), unchecked(0x00004000),
            unchecked(0x00400010), unchecked(0x20004010), unchecked(0x00000000),
            unchecked(0x20404000), unchecked(0x20000000), unchecked(0x00400010),
            unchecked(0x20004010)
        };

        private static int[] _sp7 =
        {
            unchecked(0x00200000), unchecked(0x04200002), unchecked(0x04000802),
            unchecked(0x00000000), unchecked(0x00000800), unchecked(0x04000802),
            unchecked(0x00200802), unchecked(0x04200800), unchecked(0x04200802),
            unchecked(0x00200000), unchecked(0x00000000), unchecked(0x04000002),
            unchecked(0x00000002), unchecked(0x04000000), unchecked(0x04200002),
            unchecked(0x00000802), unchecked(0x04000800), unchecked(0x00200802),
            unchecked(0x00200002), unchecked(0x04000800), unchecked(0x04000002),
            unchecked(0x04200000), unchecked(0x04200800), unchecked(0x00200002),
            unchecked(0x04200000), unchecked(0x00000800), unchecked(0x00000802),
            unchecked(0x04200802), unchecked(0x00200800), unchecked(0x00000002),
            unchecked(0x04000000), unchecked(0x00200800), unchecked(0x04000000),
            unchecked(0x00200800), unchecked(0x00200000), unchecked(0x04000802),
            unchecked(0x04000802), unchecked(0x04200002), unchecked(0x04200002),
            unchecked(0x00000002), unchecked(0x00200002), unchecked(0x04000000),
            unchecked(0x04000800), unchecked(0x00200000), unchecked(0x04200800),
            unchecked(0x00000802), unchecked(0x00200802), unchecked(0x04200800),
            unchecked(0x00000802), unchecked(0x04000002), unchecked(0x04200802),
            unchecked(0x04200000), unchecked(0x00200800), unchecked(0x00000000),
            unchecked(0x00000002), unchecked(0x04200802), unchecked(0x00000000),
            unchecked(0x00200802), unchecked(0x04200000), unchecked(0x00000800),
            unchecked(0x04000002), unchecked(0x04000800), unchecked(0x00000800),
            unchecked(0x00200002)
        };

        private static int[] _sp8 =
        {
            unchecked(0x10001040), unchecked(0x00001000), unchecked(0x00040000),
            unchecked(0x10041040), unchecked(0x10000000), unchecked(0x10001040),
            unchecked(0x00000040), unchecked(0x10000000), unchecked(0x00040040),
            unchecked(0x10040000), unchecked(0x10041040), unchecked(0x00041000),
            unchecked(0x10041000), unchecked(0x00041040), unchecked(0x00001000),
            unchecked(0x00000040), unchecked(0x10040000), unchecked(0x10000040),
            unchecked(0x10001000), unchecked(0x00001040), unchecked(0x00041000),
            unchecked(0x00040040), unchecked(0x10040040), unchecked(0x10041000),
            unchecked(0x00001040), unchecked(0x00000000), unchecked(0x00000000),
            unchecked(0x10040040), unchecked(0x10000040), unchecked(0x10001000),
            unchecked(0x00041040), unchecked(0x00040000), unchecked(0x00041040),
            unchecked(0x00040000), unchecked(0x10041000), unchecked(0x00001000),
            unchecked(0x00000040), unchecked(0x10040040), unchecked(0x00001000),
            unchecked(0x00041040), unchecked(0x10001000), unchecked(0x00000040),
            unchecked(0x10000040), unchecked(0x10040000), unchecked(0x10040040),
            unchecked(0x10000000), unchecked(0x00040000), unchecked(0x10001040),
            unchecked(0x00000000), unchecked(0x10041040), unchecked(0x00040040),
            unchecked(0x10000040), unchecked(0x10040000), unchecked(0x10001000),
            unchecked(0x10001040), unchecked(0x00000000), unchecked(0x10041040),
            unchecked(0x00041000), unchecked(0x00041000), unchecked(0x00001040),
            unchecked(0x00001040), unchecked(0x00040040), unchecked(0x10000000),
            unchecked(0x10041000)
        };

        // Tables, permutations, S-boxes, etc.
        /// Squash bytes down to ints.
        public static void SquashBytesToInts(byte[] inBytes, int inOff, int[] outInts, int
             outOff, int intLen)
        {
            for (int i = 0; i < intLen; ++i)
            {
                outInts[outOff + i] = ((inBytes[inOff + i * 4] & unchecked(0xff)) << 24)
                                    | ((inBytes[inOff + i * 4 + 1] & unchecked(0xff)) << 16)
                                    | ((inBytes[inOff + i * 4 + 2] & unchecked(0xff)) << 8)
                                    | (inBytes[inOff + i * 4 + 3] & unchecked(0xff));
            }
        }

        /// Spread ints into bytes.
        public static void SpreadIntsToBytes(int[] inInts, int inOff, byte[] outBytes, int
             outOff, int intLen)
        {
            for (int i = 0; i < intLen; ++i)
            {
                outBytes[outOff + i * 4]
                    = unchecked((byte)((int)(((uint)inInts[inOff + i]) >> 24)));
                outBytes[outOff + i * 4 + 1]
                    = unchecked((byte)((int)(((uint)inInts[inOff + i]) >> 16)));
                outBytes[outOff + i * 4 + 2]
                    = unchecked((byte)((int)(((uint)inInts[inOff + i]) >> 8)));
                outBytes[outOff + i * 4 + 3]
                    = unchecked((byte)inInts[inOff + i]);
            }
        }
    }
}
